The compounds of the present application are modulators of anaplastic lymphoma kinase (ALK) and Janus Kinase (JAK) and have a number of therapeutic applications, particularly in the treatment of proliferative diseases or disorders including certain cancers as well as hematological malignancies. Specifically, the compounds of the present application inhibit ALK and/or JAK2 kinase. Advantageously, the compounds inhibit both ALK and JAK2 kinase.
Receptor tyrosine kinases (RTKs) are enzymes which span the cell membrane and possess an extracellular ligand binding domain, a transmembrane domain, and a cytoplasmic (intracellular) tyrosine kinase domain (catalytic domain). The intracellular portion participates in cellular signal transduction by phosphorylating specific tyrosine residues in RTK substrate proteins which in turn triggers other transduction events (signal propagation). As a result, tyrosine kinases influence a number of aspects of cellular responses, such as proliferation, growth, differentiation, migration, metabolism and programmed cell death (apoptosis). It has been shown that many of these tyrosine kinases are frequently mutated and/or aberrantly expressed in a number of human disease states such as, for example, breast cancer, gastrointestinal cancers (colon, rectal, and/or stomach cancers), leukemia, ovarian cancer, and pancreatic cancer.
Some examples of RTKs that mediate various cellular responses associated with hyperproliferative disease states include c-erbB-2, c-met, tie-2, PDGRr, FGFr, and EGFR. As such, compounds that selectively inhibit or modulate the activity of one or more tyrosine kinases could provide significant therapeutic benefit in a variety of hyperproliferative disease states in mammals, including humans.
Anaplastic lymphoma kinase (ALK) is a transmembrane-spanning receptor tyrosine kinase, which belongs to the insulin receptor (IR) RTK superfamily. The most abundant expression of ALK occurs primarily in the central and peripheral nervous systems, suggesting a possible role for ALK in the development and function of the nervous system. (Iwahara, T. et al., Oncogene, 1997, 14(4), 439-449; Morris, S. W. et al., Oncogene, 1997, 14(18), 2175-2188). Mouse studies suggest that ALK may regulate the function of the frontal cortex and hippocampus in the adult brain, making ALK a possible target for psychiatric conditions such as schizophrenia and depression. (Bilsland, J. G., et al. Neuropsychopharmacology, 2008, 33(3), 685-700).
ALK is also implicated in the oncogenesis and progression of various human cancers. Specifically, an ALK inhibitor would be expected to either permit durable cures when administered as a single therapeutic agent or combined with current chemotherapy for ALCL, IMT, NSCLC, DLBCL, systemic histiocytosis, glioblastoma and other tumor types. Alternatively, an ALK inhibitor could be used in a maintenance role to prevent cancer recurrence or in patient populations that develop resistance to other therapies.
FAK (focal adhesion kinase), JAK (Janus kinase), Lck, Src, and Abl are examples of non-receptor (cytoplasmic) protein tyrosine kinases (NRPTKs). Initially, NRPTKs were identified in the context of cell growth and differentiation but subsequently the constitutive activation or abherrent expression of NRPTKs has been found to be associated with disease states characterized by abnormal cell growth, in particular cancer, in mammals.
The Janus kinase family (JAKs) consists of 4 members: JAK1, JAK2, JAK3 and TYK2. This family of kinases signals downstream from extracellular cytokines as well as various growth factor receptors. For example, the STAT (signal transduction and transcription) family of transcription factors is the principal, but not exclusive, target for JAKs. Constitutive JAK/STAT signaling is thought to play a critical role in oncogenesis and the progression of many different types of tumors by promoting multiple mechanisms of tumor pathogenesis, including cell proliferation, anti-apoptotic signaling, angiogenesis and tumor immune evasion (Yu et al. 2004). Moreover, constitutively activated JAK/STAT signaling is found in many tumor types, but not in normal tissues (Yu et al. 2004; Benekli et al. 2003). The ability of the JAK/STAT pathway to mediate resistance to apoptosis is particularly important, as most anti-cancer drugs affect tumors by inducing apoptosis.
The importance of these kinases in cellular survival is made evident by the fact that the loss of JAKs is often accompanied by immunodeficiency and non-viability in animal models (Aringer, M., et al.). The JAK family of enzymes is characterized by a number of JAK homology (JH) domains, including a carboxy-terminal protein tyrosine kinase domain (JH1) and an adjacent kinase-like domain (JH2), which is thought to regulate the activity of the JH1 domain (Harpur, A. G., et al.). The four JAK isoforms transduce different signals by being associated specifically with certain cytokine receptors, and activating a subset of downstream genes. For example, JAK2 associates with cytokine receptors specific for interleukin-3 (Silvennoinen, O., et al., Proc Natl Acad Sci USA, 1993, 90(18): p. 8429-33), erythropoietin (Witthuhn, B. A., et al., Cell, 1993, 74(2): p. 227-36), granulocyte colony stimulating factor (Nicholson, S. E., et al., Proc Natl Acad Sci USA, 1994, 91(8): p. 2985-8), and growth hormone (Argetsinger, L. S., et al., Cell, 1993, 74(2): p. 237-44).
The JAK family of enzymes has become an interesting set of targets for various hematological and immunological disorders; JAK2 specifically is currently under study as a viable target for neoplastic disease, especially leukemias and lymphomas (Benekli, M., et al., Blood, 2003. 101(8): p. 2940-54; Peeters, P., et al., Blood, 1997. 90(7): p. 2535-40; Reiter, A., et al., Cancer Res, 2005. 65(7): p. 2662-7; Takemoto, S., et al., Proc Natl Acad Sci USA, 1997. 94(25): p. 13897-902) as well as solid tumors (Walz, C., et al., J Biol Chem, 2006. 281(26): p. 18177-83), and other myeloproliferative disorders such as polycythemia vera (Baxter, E. J., et al., Lancet, 2005. 365(9464): p. 1054-61; James, C., et al., Nature, 2005. 434(7037): p. 1144-8; Levine, R. L., et al., Cancer Cell, 2005. 7(4): p. 387-97; Shannon, K. and R. A. Van Etten, Cancer Cell, 2005. 7(4): p. 291-3), due to its activation of downstream effector genes involved in proliferation. JAK2 is also known to be mutated in hematologic malignancies, such that it no longer requires ligand binding to the cytokine receptor and is instead in a state of constitutive activation. This can occur through translocation between the JAK2 gene with genes encoding the ETV6, BCR or PCM1 proteins (Peeters, P., et al.; Reiter, A., et al.; Griesinger, F., et al., Genes Chromosomes Cancer, 2005. 44(3): p. 329-33; Lacronique, V., et al., Science, 1997. 278(5341): p. 1309-12) to create an oncogenic fusion protein, analogous to the BCR-ABL protein seen in chronic myelogenous leukemia. Overactivation of JAK2 can also occur through mutation of the JAK2 sequence itself for example, the myeloproliferative disease polycythemia vera is associated with a point mutation that causes a valine-to-phenylalanine substitution at amino acid 617 (JAK2 V617F) (Walz, C., et al.).